The series 9 is best in class for sleep accuracy: https://www.youtube.com/watch?v=Jr4p66vSmLY https://www.youtube.com/watch?v=Jr4p66vSmLY (18:20 mark) We're no

The series 9 is best in class for sleep accuracy: https://www.youtube.com/watch?v=Jr4p66vSmLY https://www.youtube.com/watch?v=Jr4p66vSmLY (18:20 mark) We're now four generations of Apple Watch beyond yours.